Design is about making choices—deciding to use one font over another, what information to display, or what feature has prominence on a page. Design choices can be as much about what elements to include, as they are about how to display the information and its functionality.

But how do we make these choices? Is it just our gut instinct? Is it what we like? Clients hire us partially for our unique perspective but they expect us to apply that perspective in an informed way. They want us to make choices based on our users and on meeting their specific needs and goals. The work we do for our clients should help them be more successful, make more money, reach more customers, communicate more clearly, and make great customer experiences.

By understanding and prioritizing what both our clients and their customers want, we can make the strongest design choices. Prioritized goals inform choices, mediate arguments, and help determine when a design is successful.

One of the first steps in any design process is to understand what you are building. Kick-off meetings and deep dive sessions with client representatives help a designer understand what his client wants—the client's business goals, who they think their users are, and any features or functions they've already imagined—but often this kind of brain dump can make a designer feel as if his client wants everything.

Your best friend in these initial meetings are sticky notes.

It's important to create the impression that nothing is set in stone yet. Not features, functions, users, or business goals. As you progress through design, learn more—about your competition and your users—and begin to make choices. Doing so, the design will become more concrete. But in these initial kickoff meetings, it's important to be open to all the different options and visions.

Start out each exercise—whether you're defining business goals, or user types—by being open to everything. Encourage your clients to share all their ideas. And when they do, write it down and stick it on the wall. When you come up with your own ideas, write them down too and stick 'em. You will be pleasantly surprised at the kinds of conversations this type of activity can create.

Once you've got a solid list of all the options on the wall, start to group the "like" options together. Pull a sticky off the wall, and re-stick next to one that's similar. It's good to get all your clients involved in this. Put them in groups of 2 or 3, get them on their feet and have them group stickies. Again, this will create more useful conversations as they discuss and debate why some stickies belong with other stickies.

Eventually you'll create a set of groupings, which should be named. Each grouping is your initial business goal or user type. Write each grouping name on another sticky. And stick it.

Now it's time to prioritize. Draw a pyramid on a whiteboard or large sticky sheet. Explain to your clients the 20/30/50 rule—20% of their goals should be high priority, 30% medium priority, and 50% low—and set them loose. Have them work in groups to move the newly defined business goals or user types onto the pyramid. Encourage discussion and debate. You can learn just as much from listening to their internal discussions as you can by the final prioritization of goals or users.

Excerpted from Interactive Design: An Introduction to the Theory and Application of User-Centered Design, by Jason Nunes and Andy Pratt, due out in September.